Cardiology Partners

Cardiology

Our dedicated veterinary specialists are here to help you and your pet live with heart disease.

No one wants themselves or their pet diagnosed with heart disease, but heart conditions are common in dogs (and cats, to a lesser extent), just like they are in people. Pets with heart disease, just like people, benefit from the care of a specialist – a cardiologist.

It may seem obvious that a cardiologist is a “heart doctor.” Just like cardiologists that treat people, veterinary cardiologists receive special training – several years’ worth. Cardiology is a sub-specialty of internal medicine, so a true “cardiologist” is a board-certified internal medicine specialist that has done an additional residency in cardiology. ASG’s cardiology team is led by Dr. Fred Brewer, a published, experienced board-certified cardiologist. He and his team are here to help you and your pet live with your pet’s heart disease.

There is more than one type of heart disease.

The heart functions as a pump, with four hollow chambers separated by one-way valves and surrounded by muscular walls. These muscles contract in a special rhythm to push blood through the lungs, back to the heart, and then out to body, providing the tissues and organs with the oxygen needed for almost every function.

Given this definition, it makes sense that heart disease in dogs and cats generally falls into one of three major categories: diseases of the heart muscle, disease of the heart’s nervous system, and diseases of the valves that separate the chambers.

Humans (and parrots) have problems related to the coronary arteries, who are responsible for supplying the heart muscle with oxygen. Hardening and clogging of these vessels causes lack of oxygen to the heart muscle itself, and this termed a myocardial infarction (MI or “heart attack”). Fortunately, this is an extremely rare condition in dogs.

Heart muscle disease: Heart muscle disease (cardiomyopathy) is seen most commonly in large dog breeds, such as Golden retrievers, German shepherds, Doberman pinschers, Boxers and Great Danes. In these dog breeds, the heart muscle gradually weakens, and the pumping function of the heart is affected. Over time, because the contraction is weaker, the chambers become overfilled with blood, and the heart gets physically larger. Cats had the same problem until 1987, when it was discovered that dilated cardiomyopathy in cats was almost always caused by a taurine deficiency. Since that time, commercial cat foods have been supplemented with taurine, and this problem has largely disappeared.

Cats (and rarely dogs) can develop different forms of muscle disease called hypertrophic or restrictive cardiomyopathy. In the case of hypertrophic cardiomyopathy, the heart muscle doesn’t get weaker, it gets thicker. In restrictive cardiomyopathy the heart chambers may become enlarged and weakened. Both diseases have been shown to be associated with genetic mutations of which there may be multiple genetic causes for their development. Similarly, both disease can lead to congestive heart failure. Hypertrophic cardiomyopathy can lead to extremely thickened heart muscles, which reduce the size of the chambers, increasing pressure in the heart which eventually leads to fluid accumulation (congestive heart failure). In cats with restrictive cardiomyopathy the hearts are infiltrated by fibrous tissue (scar tissue), which affect both the squeezing and relaxing abilities of the heart. This too will lead to fluid accumulation (congestive heart failure).

Nervous system disease: Nerve impulses that cause the heart muscle to contract are under the control of specialized pacemaker tissues. These nodes control the timing of the contraction of the chambers like the distributor in a 70s-era muscle car controls the timing of the pistons in the engine. When that timing is off, the heart does not function normally (not “firing on all cylinders”). When the electrical signal is altered the rhythm in which the heart beats is disrupted, resulting in an arrhythmia.

Arrhythmias have a large number of causes, including hereditary, problems with the conduction pathways of the heart, disease of the heart muscle (cardiomyopathy), trauma, cancer, and metabolic or systemic disease. Some arrhythmias can be controlled with medication, while others require more intervention (like having a pacemaker placed).

Valvular disease: Valves separate the upper heart chambers (atria) from the larger lower chambers (ventricles), and also separate the ventricles from the great vessels. The circulatory system is designed as a one-way loop, and these valves prevent the flow of blood in the wrong direction.

However, sometimes these valves don’t serve well as one-way doors, due to the presence of parasites (heartworms), degenerative disease (mitral valve disease), trauma, or infectious/inflammatory disease (endocarditis). In general, smaller dog breeds have valvular disease, where larger dogs have cardiomyopathies. When blood flows in the wrong direction, it causes the chambers to become overloaded, and this causes congestion, just like cars going the wrong way on the highway would cause a problem.

Diagnosing the problem through sight and sound.

ASG’s cardiology team uses the most advanced technology to diagnose your pet’s heart disease. These same technologies are used to monitor your pet over time. Most cardiac patients will have multiple tests done, including ECG, chest radiographs, and ultrasound/echocardiography as initial screening tests.

Electrocardiogram/electrokardiogram (ECG or EKG): Electrical disturbances are diagnosed with an electrocardiogram. Similar to the setup in people, electrodes placed around the chest or on the limbs allow us to measure the electrical impulse as it moves through the heart, and helps identify exactly where the problem lies. In some patients, the electrical abnormality doesn’t happen with every beat – sometimes patients will go hours in between episodes. For these patients, a wearable ECG sensor called a Holter monitor is used to record the ECG for 24 hours.

Picturing the heart and lungs: In many cases, radiographs of the heart are helpful to assess the size of the heart chambers. These radiographs also give us an opportunity to evaluate the lung tissue as well as the size and shape of the blood vessels within the chest. Radiographs are also useful tools for monitoring your pet’s response to diuretic therapy, and periodic radiographs may be taken to gauge response to therapy or progression of a heart condition.

Seeing with sound: While radiographs are an important tool for assessing the size of the heart and the condition of the lungs, the gold standard for evaluating the heart since the 1980s is an ultrasound exam called echocardiography, literally looking at the heart with sound waves. So safe that it is used on expectant mothers to view their as-yet-to-be-born babies, ultrasound is ideal for evaluating the moving, beating heart. Because it is a moving picture, the valve function can be checked, and turbulent blood flow can be identified with the color Doppler function. The size of each chamber, the thickness of the walls, and the strength of each contraction can be measured and recorded.

These vital statistics are used initially to diagnose your pet’s heart condition. Our skilled team also uses these numbers to objectively track the progress of your pet’s condition and tailor the therapy and medication precisely.

Quality of Life comes first.

Heart disease in pets is serious business, and we take it seriously. At ASG, nothing is more important to us than the quality of your pet’s life – it is the very reason for our existence. Our cardiologist, often in conjunction with your family veterinarian, uses the most advanced technology and medication to maximize that quality of life of your pet for as long as possible.